Field of the Invention
This invention relates to a bushing assembly for electrical apparatus and, more particularly, to a low voltage bushing for a distribution transformer.
Description of the Prior Art
Copper has been the customary metal employed for transformer secondary coil leads or conductors. Due to extraordinary cost increases of copper, aluminum has been adopted as a substitute for use as leads or conductors of the secondary windings of distribution transformers. Although aluminum is an excellent electrical conductor, electrical grade aluminum is extremely soft and therefore has presented problems. Electrical grade aluminum in the dead-soft, annealed condition has a very low creep strength and therefore has a tendency to cold flow out of a connector assembly when any compressive force is applied. The problem is particularly prevalent where aluminum is clamped in a connector assembly such as in the terminal connector between internal and external sides of a transformer casing.